I've discovered that Windows 7 makes it very difficult to use DCOM and, mainly, the GlassFish clustering commands that rely on DCOM. I spent a few days trying to solve the problems. I don't yet have a cookbook for making DCOM work on Windows 7. But here are a few tips and advice I've found.
3. When I ran validate-dcom on my Windows 7 network I saw the problem below:
Successfully resolved host name to: gloin/10.28.51.10 Successfully connected to DCOM Port at port 135 on host gloin.
Successfully connected to NetBIOS Session Service at port 139 on host gloin.
Successfully connected to Windows Shares at port 445 on host gloin.
Can not access the remote file system. Is UAC on? : Access is denied.
I discovered the actual problem is that Windows 7 no longer has the "C$" Administrative file share available by default. If "C$" isn't available then nothing will work. Here is how to expose the "C$" share:
Registry Change -- this change allows “C$” to be accessed. As soon as I set it -- the file copying started working! 
create this key, 32 bit word, with value == 1
4. Turn on the Remote Registry Service -- This is critical and it's easy to do. Windows 7 has it turned off by default. MyComputer-right click, manage, services, then turn on Remote Registry Service and set it to start automatically in the fture.
5. Turn off UAC: %systemroot%\system32\UserAccountControlSettings.exe
6. This is where I discovered that McAfee virus scanner blocks all the NetBios shares! It has to be disabled.